Sharpening device.



y R. CANDELIEZ.

SHAHPENING DEVICE,

APPLICATION FILED JUNE I8. I9I4.

1,240,540. Patented Sept. 18, 1917.

F5/ig: j.

BENE GANDELIEZ, on UccLE, BELGIUM.

SHARPENING DEVICE.

Specification of lLetters Patent. Patented Sept, 18, 1917,

Application filed .Tune 18, 1914. Serial No. 845,810.

To all 'whom t may concern:

4Be it known that I, REN CANDELIEz, citizen of the French Republic,residing at Uccle 307, Rue Vanderkindere, Belgium, have invented a newand useful Improvement in Sharpening Devices; and I do hereby declarethe following to be a full, clear, and exact description of the same.

This invention is based on the following theoretical considerations,reference being had to razors, as an example.

Figures 1 and 2 are diagrammatic crosssectional views which taken withthe description explain the theoryY of the applicants device;

Fig. 3 is a plan of the sharpening device, part being removed.

Fig. 4f is a fragmental longitudinal section, taken on the line Z-d ofFig. 3; and

Fig. 5 shows a view partly in cross-section on the line e-e of Fig. 3.

When, as is generally the case, a razor is being sharpened, the originalcross-section of which is C D E (Fig. l), on a strop attached to aneye-bolt, or on a leather A B stretched flat on a bar, it will bereadily understood that the cutting edge C is worn out and disappears,the more quickly, the greater the thickness of the blade relatively toits width, and that it has the tendency to assume the defective shape cD E (the portion shown cross-hatched) or in other words, that thefriction quickly blunts the edge and that the latter can be no longerformed again, except on a thicker portion 0 of the blade, which is oneof the most unfavorable conditions to the sharpening and to the life ofthe razor.

In order to obviate this too quick wearing out, it will be logical tohave for the friction plane A B substituted VVa portion a C E b (Fig. 2)of a circle with center C, tangent at C to the curvature C E of therazor blade, so that the median line C H ofthe symmetrical curvatures CD, C E of the said blade, which is also their common tangent, coincidesat C with the tangent to the circle whose center is C and that thus thesharpening is only made tangentially to the cutting edge withoutblunting it, as is the case with flat leather.

Among all the circles tangent to the cutting edge C, the most suitableone is obviously the circle having the same radius of curvature, as theblade at the said point C, that is to say, the circle tangent to the thehand which guides the blade on an arc of very small radius, in practicewould have very great dificulty in maintaining, during the friction ofthe blade, simultaneous contact at the back and the edge of the razor. YThe real solution of the problem consists in considering as elastic theportion C E of the arc of circle arranged under the blade. By examiningFig. 2, it will be seen in fact that the central tangent C H is at adistance E I-I from the straight line G E parallel to it and passingthrough E, equal to If therefore we slide the back of the razor along CrE, keeping C H parallel to the said straight line G E, it will besuflicient if at each new position of the blade, we should always meet apoint C of the sharpening device situated at the distance of from G E,

in order that the sharpening should take place tangentially to thecutting edge, which is the desired result.

This condition is fulfilled in the device, forming the obj ect of thepresent invention and which is illustrated, by way of example, in theannexed drawings.

The device is shown in plan in Fig. 3. The leather K covering, betweenits edges I, I, L, L, is assumed to have been removed for half itslength. It will be seen that the handle Q is made removable, and can besecured by screwing, or in any other way` at'either end of theinstrument.

Fig. 5 is a cross-section on line ew@ (of Fig. 3) which is the mostsuitable for the explanation and which shows at M the hard wood barforming the frame of the instrument. This bar is provided at each sidewith an extension J at a right angle to its plane and forming asupporting ledge. Between the said supporting ledges J J of equalheight, is placed an elastic part constituted by a leather envelop V0rcase K K covering a system of several rubber tubes F F embedded in abase-l), also of rubber. The leather case thus provided with tubes, islined. inside with paper or fabric impermeable to grease in order toprotect the rubber of the tubes. lts face in contact with the base l)adheres by gluing to the inner bottom N N of the bar. The distance fromthe upper plane of the ledges to the upper plane of the leather of thecase is substantially equal to half the thickness of the back of therazor.

In these conditions, if the said back is caused to slide by strongly andevenly pressiug it on both ledges atv the same time, and if the edge ofthe razor is heldv on the leather li previously coated With razor paste,without pressing or pressing very slightly on the edge, the Working ofthe elas-y tic part will comply exactly with the indications of Fig. 2,that is to say, the cylindrical surface which is constantly formed againunder the blade, betiveen the back sliding on the ledges and the cuttingedge, remaining tangent to the leather, ivill produce in any positionofthe said blade, the circle tangent to the cutting edge. The sharpeningis therefore effected tangentially to the latter', and no longerobliquely.

It must be pointedout here Vthat the elastic part must be able toundergo a comparatively considerable deformation. It Would not besufficient in fact to place for instance the leather on an ordinarycotton fabric of 1 2 mm. thickness. lt is necessary that the differencein level of the surface of the leather -should be able to reach ifrequired a value practically equal to half the thickness ofthe back ofthe razor, that is to say, in practice from lwe mm. Although differentmeans such as folded fabrics or specia-l cotton, Wool, horse-hair, etc.,fabrics, steel or other springs, metal fabrics, Wires, rubber points,etc., could be used for attaining the object of the invention Withoutdeparting from the principle thereof, nevertheless the idea ofconstituting the elastic part by a system of rubber tubes parallel tothe bars, in the principal feature of the invention however' the saidtubes be placed, Whatever be their number, even one, Which could be anair tube similar to the inner tube of bicycles.

Also, the form illustrated seems to be the best adapted for the handle Qof the instrument. The said handle is made removable and can be fixed toeither extremity of the bar so that, when changing its place from timeto time, the elast-ic portion and the leather of the instrument willWork and Wear out'both symmetrically and uniformly. Any other suitablemeans could also be used for the same purpose.

The present invention can be applied Without any changes being made, toany kind of Vsharp blades, particularly to razor blades of It goesWithout saying that the instrument can be double-faced, symmetricallywith respect to the straight line T V dividing the thickness ofthe barinto equal parts.

It goes also VWithout saying that the theo-` retical distance frointhetop of the ledges to the top of theleather can be slightly or more orless modified, Without departing from the invention. If required,thesaid ledges could even be dispensed With, the back of the razorl beingin this casesupported by the flattened tubes. Furthermore, the envelopcan be made of twisted fabric or of any material other than leather, andits surface, in contact With the bar, can be dispensed With, the elasticportion restingin this case directly on the said bar.

Having fully describedv my invention, what I claim and desire tosecureby Lets ters Patentis:.

l. In a domestic-sharpening device the combination .ofzabar -a leatherenvelop; and a plurality ofparallel longitudinal tubesof uniformdiameter, arranged side-by-side combination of a bar; a leather envelop;

and a plurality ofparallel elastic tubes open to the outside air andoffunifornidiameter, arranged sidefby-.side under said envelop, saidtubes permitting the envelop to bedeformed andto .adopt the fornivofrthe blade andcuttingedge from end-to-end thereof.

4t. A sharpening device, comprising in combination, a bar, two lateral,longitudinal ledges of uniform height and perpendicular tothe. bar, aleather envelop arrangedbetween thesaid ledges andresting onthe bar,rubber tubes arranged in the interior of the leather'envelop, parallelto thelong sides of the bar, a rubber base in Which are embedded; thesaid tubes, substantially as described. 1

5... A sharpening device, comprising in combination, a bar, two lateral,longitudinal ledges ofruniform height and perpendicular to the bar, aleather envelop arranged betu'een the said ledges and resting on thebar, rubber tubesarranged in the interior` ofthe the bar and the innerdiameter of whichV is equal to half the thickness of the thick portionof the blade to be sharpened, substantially as described.

6. A sharpening device, comprising in combination, a bar, two lateral,longitudinal ledges of uniform height and perpendicular to the bar, aleather envelop arranged between lthe said ledges and resting on thebar, the said leather envelop being rendered impermeable to grease so asto protect the rubber, rubber tubes arranged in the interior of theleather envelop, parallel to the long sides of the bar, substantially asdescribed.

7. A. sharpening device, comprising in combination, a bar, two lateral,longitudinal ledges of uniform height and perpendicular to the bar, aleather envelop arranged between the said ledges and resting on the bar,rubber tubes arranged in the interior of the leather envelop, parallelto the long sides of the bar, and a handle constructed to be fixed toeither end of the bar, substantially as described.

8. A sharpening device, comprising, in combination, a bar, a leatherenvelop, uniform rubber tubes parallel to each other and arrangedlongitudinally under said envelop, the said tubes allowing the leatherenvelop to be deformed and adopt the form of the cutting edge in allpositions of the blade to be sharpened, substantially as described.

In testimony whereof, I have signed my name to this specification.

REN GANDELIEZK.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C.

